Back pain (e.g., low back pain (LBP) lasting approximately 12 weeks) affects approximately tens of millions of people in the U.S. and is the second leading cause of disability (6.8 million people). Back pain is associated with reduced activities of daily living (e.g., walking, housework, personal care) and health-related quality of life. In addition, back pain is expensive to treat and often leads to missed work days (149 million days/year) and reduced productivity, resulting in total costs of $100-200 billion/year in the U.S.
Present methods to relieve back pain are ineffective, expensive, inconvenient, and/or invasive. For example, oral medications (e.g., acetaminophen, NSAIDs, muscle relaxants, tricyclic antidepressants, antiepileptics, and corticosteroids) provide only limited and/or short-lived pain relief, and typically produce side effects (e.g., sedation, dizziness, and gastrointestinal problems). Although opioids can provide substantial short-term pain relief, they are not recommended as a treatment to control chronic back pain, since long-term use can result in dependence and severe side effects.
Exercise (including yoga, stretching, strength training) has a low level of risk and can relieve pain and improve function long-term, but patients often fail to comply with treatment regimens due to discomfort, lack of motivation, and inconvenience.
Physical manipulation (i.e., massage, spinal manipulation) has a low level of risk and can provide short-term pain relief. However, evidence for the long-term benefit of physical manipulation has been mixed. Further, frequent treatment sessions are required to maintain pain relief, which is inconvenient for patients.
Acupuncture is minimally-invasive, and studies have suggested that acupuncture can provide pain relief. However, study design in acupuncture studies has been questionable (e.g., adequacy of sham/placebo/control), and the effectiveness of acupuncture remains controversial.
Injections of steroids or anesthetic provide short-term pain relief but seldom produce long-term benefit. As well, injections of such medicines produce side effects, including increased pain, lightheadedness, headache, infection, and nausea and vomiting.
Intrathecal drug therapy can be effective for reducing pain but requires an invasive procedure and is limited by a host of frequent side effects (e.g., nausea, infection, intrathecal granuloma). Also, technical complications (i.e., problems with catheter or pump) are common and may require reoperation or removal of the device.
Surgical procedures for back pain (e.g., spinal fusion, disc replacement) are highly invasive, irreversible, carry risks of complications, and reduce pain in less than half of patients. Also, surgeries for chronic back pain frequently require reoperation.
Existing methods of electrical stimulation reduce pain by generating paresthesias (i.e., tingling sensation) overlapping the regions of pain. Pain relief using these existing methods persists only for a short time following treatment (e.g., hours to days), and this suggests that chronic pain has not been reversed. As a result, only a small percentage of patients using existing methods of electrical stimulation experienced clinically significant reductions in chronic axial low back pain post-treatment.
TENS is a non-invasive method to deliver electrical stimulation through surface electrodes to generate paresthesia coverage of the regions of pain. TENS requires frequent treatment sessions to maintain pain relief, but consistent efficacy in chronic low back pain has not been demonstrated. Although TENS can be self-administered at home, TENS systems are cumbersome and not practical for daily use. Also, TENS can activate cutaneous fibers and cause irritation and discomfort, limiting the maximum tolerable stimulation intensity and treatment duration that can be delivered and reducing the potential efficacy of the treatment.
Spinal cord stimulation is a method to deliver electrical stimulation through implanted leads connected to an implanted pulse generator to generate paresthesia coverage of the regions of pain. Spinal cord stimulation requires complex and invasive surgery to implant the leads and pulse generator. Spinal cord stimulation has a moderate rate of complications, including additional pain and hardware complications, and as a result, revision surgery, reprogramming, or removal of the stimulator is often required.
In summary, present treatments for back pain seldom provide adequate long-term relief of pain or improvements in function; carry risks of side effects and complications; and/or are invasive.
There remains room in the art of pain management for unproved systems and methods to be used to assist in the treatment of back pain.